The present inventions relates to a system for computerized energy management, more particularly to an apparatus for controlling lighting luminaries whose light output, power consumption, and parameters can be monitored and controlled as part of the distributed building control network.
In the field of computerized energy management in large buildings energy conservation is very important. The systems used presently utilize a distributed computing approach to control heating, ventilation and some lighting management. In addition, some systems may incorporate miscellaneous functions such as security monitoring and control, and fire and burglar alarm management. In many buildings, control and monitoring are performed by a centralized computer connected to the network.
The central computer may actually reside in a remotely located building and communicate via telephone, satellite, or other means. The connections within the network itself may include multiple media, including a twisted pair or coaxial wiring, power line signaling, fiber-optic cabling and rf links. Networks of this type do not necessarily need a centralized control computer to coordinate activities.
It is possible to organize a network so that it serves as a means for communication between micro-controllers distributed throughout the building. In this approach their actions are coordinated by their internal control programs. An example of this would be a case whereby a switch closure signal sent to one luminaire to energize its lamps is then relayed by its micro-controller over the network to a number of other luminaries to energize them as well. This discussion assumes that a central computer performs the principal control and monitoring functions of a energy management system.
The state of the art micro-controllers networks being used are LonWorks(copyright), and CEbus(copyright). The micro-controller devices are embedded within the equipment being controlled and is distributed across a building on a network that may consist of different topologies including a star, ring and point to point topologies. The prior art as described in U.S. Pat. No. 5,381,078 entitled xe2x80x9cControl and Communication Processor Potentiometer System for Controlling Fluorescent Lampsxe2x80x9d, is one such control system. This control system uses a distributed LonWorks(copyright) micro-controllers containing electronic potentiometers mounted on a wall and lighting controllers mounted on ceiling to set the dimming level of a number of dimmable slave ballasts under its control. However, the control system does not sense ballast parameters.
The following is a discussion of the dimming ballast circuitry, its means of dimming control, and its interface to the embedded micro-controller. The discussion centers around a design that uses the ML4832 integrated circuit (IC) ballast controller chip made by MicroLinear, 2092 Concourse Drive, San Jose, Calif. 95131. This IC is similar to that described in U.S. Pat. No. 5,315,214, entitled xe2x80x9cDimmable High Power Factor High-Efficiency Electronic Ballast Controller Integrated Circuit with Automatic Over-Temperature Shutdownxe2x80x9d, by Lesea, dated May 24, 1994. This IC combines power factor correction functions and ballast control in one IC. Approaches using other IC devices should be obvious to those skilled in the art. Sectioned schematic diagrams will be shown for clarity is describing the essential points of the invention, the details not explained can be found by referencing the MicroLinear literature.
Next, the system for dimming a fluorescent light is described in U.S. Pat. No. 3,697,821. In the aforementioned patent, a semiconductor multiple remote control unit have been used to switch and dim lights. A remote control unit is provided for individually and independently controlling the brightness of the lamps independently controlling the operation of a common lamp dimmer unit by turning on and off the dimmer unit and controlling the brightness of the lamps independently of previous settings or condition of the remote control units. A three wire conductor system is used to connect the various remote control units that are in parallel to one another.
The next prior art invention relates to controlling a household lighting circuit, U.S. Pat. No. 4,733,138. The aforementioned patent is a programmable lighting circuit controller for controlling a plurality of household lighting circuits. The invention includes a microprocessor and an electronically erasable programmable read-only memory for programming household lighting circuits for a variety of loads. One of the lighting circuits may include fluorescent loads by using a heater circuit for the fluorescent lamps. The microprocessor is controlled to raise and lower lighting levels, set lighting levels in memory and recall preset levels from memory, as well as to provide heating for fluorescent lights.
The prior art inventions are all related to controlling the light by either electronic potentiometers, semiconductors or a microprocessor with an erasable read only memory. However, the prior art does not use the lighting circuitry to control the energy management in large buildings.
It is an object of this invention to provide an electronic lighting ballast that contains an interfacing means of connecting the ballast to a building computer network for the purposes of ballast control, ballast and luminaire monitoring of light output, energy usage, lamp current, and ballast temperature, environmental monitoring including nearby light levels, and room temperature, and control and monitoring of other nearby luminaries. Such a network can be interconnected to local utility companies so that lighting in large buildings can be selectively managed in times of high power demand to help balance system loading.
It would be advantageous to provide an electronic lighting ballast that contains a computer interface incorporating a micro-controller system to provide control and monitoring functions under operation of a program stored in its own computer memory.
It would also be advantageous to provide an electronic lighting ballast that contains within it means of powering said computer interface and micro-controller circuitry.
It would also be advantageous to provide an electronic lighting ballast that contains means for connection of light detection sensors, occupancy sensors, temperature sensors, and other environmental sensors that are located remote from the luminaire.
It would also be advantageous to provide an electronic lighting ballast that contains means for controlling and monitoring other nearby incandescent or gas discharge lighting luminaries, such means include control by means of the micro-controller contained within the luminaire, or control by commands obtained from the energy management control network.
It would also be advantageous to provide an electronic lighting ballast that contains means of identification to the control computer network, and means of identifying each luminaire under its control to the energy management control network.
It would also be advantageous to provide an electronic lighting ballast that contains within it means of modulating light for communication purposes, with data to be communicated being obtained from the distributed building control network through a computer interface means contained within the ballast unit.
It would also be advantageous to provide an electronic lighting ballast that has the above control, and monitoring features, but the computer interfacing and micro-controller circuitry is located nearby the luminaire so that it contains its identity to the building computer network.
The present invention is motivated by the fact that the systems being used now does not have an energy management system that produces a lighting luminaire whose light output, power consumption, and parameters can be monitored and controlled as part of the distributed building control network. The present invention uses control networks that can be connected to the local utility so that lighting in large buildings can be cut back in times of high power demand to help balance system loading. A key part of the present invention is an electronic lighting ballast that can be connected to the network. The unit would permit control of many fluorescent and gas discharge lighting fixtures within a large building and would allow more effective management of lighting energy usage. In addition, from a system maintenance viewpoint, functions such as lamp or ballast replacement could be more effectively managed. Further, as lamps age the maintenance of lumen output could be tracked on a continual basis throughout a building.
The present invention describes an electronic ballast for powering fluorescent or other gas discharge lighting lamps that contains special circuitry that allows connection to be distributed to a building control computer network for the purposes of controlling lighting functions, such as power on/off, dimming control, and the number of lamps connected to an individual ballast, and monitoring ballast parameters such as lamp light output, lamp current, ballast power consumption, ballast temperature, as well as room environmental conditions. If the special circuitry includes a small micro-controller unit, the ballast would be able to perform control and monitor functions by means of a program stored within its own micro-controller memory, such functions may be coordinated from the building control network. Other capabilities include monitoring of ballast operation, sensing of light levels within and/or outside of the fixture, and sensing of other environmental parameters such as the output of motion detectors that sense room occupancy, room temperature and humidity. Still other capabilities include control of other ballasts in nearby luminaries, and control of other lighting luminaries that may contain standard incandescent lighting, and connection of other room monitoring sensors located remotely from the luminaire. Still other capabilities include transmission of data over a communication channel formed by modulation of the luminaire output as by various methods of including amplitude, frequency or phase modulation means within the ballast, with the data source being part of the distributed building computer network. Ballasts with information transmission means are discussed in co-pending patent application xe2x80x9cFluorescent Light Ballast with Information Transmission Circuitryxe2x80x9d, by Katyl and Murcko, file number 08/632,297,.
Another desirable feature in an electronic ballast is local control capability which would allow it to turn on or off or set a dimming level according to control instructions contained within its own micro-controller memory. The micro-controller within the ballast would be linked to the building control micro-controller and could be re-programmed through it. With additional interfacing capability, other nearby ballasts that have the proper circuitry installed could also be controlled by the control ballast that is connected to the building network.